Serena seals spot in quarter-finals

Serena Williams twice came from behind to get the better of Maria Kirilenko and advance to the quarter-finals of the China Open.

The world No. 1 saved three sets points in the opening set but was still able to emerge unscathed in a 7-5 7-5 win. Kirilenko broke Williams at 5-4 and was 40-0 up in the first set. Williams though fought back to take it herself.

And again it was Kirilenko who held the advantage in the second set, leading 4-2, but Williams recovered to clinch her 70th victory of the campaign to see off the 2005 champion.

"I just thought, 'What else can I do except fight for this point and the next point,'" Williams said on the moment she faced three set points.

"Maybe I got lucky a little bit - I just started to relax and kind of swing and not think about it too much out there. I'm obviously just really happy to get through this match today."

Former world No. 1 Caroline Wozniacki will be Williams' quarter-final opponent after the Dane defeated Sloane Stephens 6-3 6-1.